The present invention relates to a carrier transporting apparatus for use in an immunological analysis which supplies and/or discharges the predetermined number of carriers into and/or from successive reaction vessels.
Nowadays, due to the progress in medical treatment, very small amounts of biological substances in samples can be analyzed and this contributes to early diagnosis for various diseases. For instance, malignant tumors which may be detected by measuring an abnormal increase of .alpha.-fetoprotein and carcinoembryonic antigen, diseases caused by abnormal secretions of hormones such as insulin and thyroxine, and immunological diseases caused by an abnormal increase or decrease of immunoglobulin can be diagnosed in early stages by means of biochemical analysis. Further, monitoring after treatments for these diseases can be carried out reliably. Moreover, the measurement of incomplete antigens, i.e. low molecular hapten of medical substances contributes to the development of a plan of medication.
Many biological substances are analyzed in an immunological manner by utilizing the antigen-antibody reaction and various methods for effecting the immunological analysis have been developed.
In one of well-known methods, there has been developed a method which utilizes antigen or antibody coupled with labeling material which detects antigen-antibody compounds at a high sensitivity.
The analytic methods using the markers are classified into radio-immuno-assay using radioisotope tracers, fluorescent-immuno-assay using fluorescent labeling material, and enzyme-immuno-assay using enzyme markers. Among these methods, the enzyme-immuno-assay has been particularly developed owing to the reason that it does not require special installation and measuring techniques and can be performed easily by using commonly developed colorimeters. The enzyme-immuno-assay is further classified into homogeneous enzyme-immuno-assay and heterogeneous enzyme-immuno-assay. In the homogeneous analysis, a variation in activity of labeling enzyme due to existence or non-existence of the immunological reaction is directly measured to detect substances to be analyzed. In the heterogeneous analysis, use is made of insoluble carriers such as glass beads or synthetic resin particles on which antigen or antibody has been fixed, enzyme-labeled antigen or antibody bound with the antibody or antigen fixed on the carriers and free enzyme-labeled antigen or antibody not bound with the antibody or antigen on the carriers are separated from each other by washing treatment, and then an activity of labeling enzyme is detected to measure a quantity of substances to be analyzed. Hereinbelow, the process for separating the bound antigen or antibody and the free antigen or antibody from each other is termed as B-F separation for the sake of simplicity. Although the homogeneous analysis can be performed by simple processes, it can analyze only the low molecular hapten such as medical substances, but cannot analyze high molecular biological substances. Contrary to this, in the heterogeneous analysis, although the washing process is required for effecting the B-F separation, it can be applied to any kinds of low and high molecular substances. Therefore, recently the heterogeneous enzyme-immuno-assay has been generally adopted.
In the heterogeneous enzyme-immuno-assay, there have been developed competitive method and sandwich method. Now these methods will be explained with reference to the drawings.
FIG. 1 illustrates successive steps of the competitive method. A given antigen or antibody which reacts with antibody or antigen substances 2 of a sample has been previously fixed to an outer surface of a insoluble carrier 1. At first, the antigen-antibody reaction is carried out between the antigen or antibody fixed onto the carrier 1 and the antibody or antigen 2 in the sample as well as a labeled reagent 3 which has been prepared by labeling substances which are the same as the substances 2 to be analyzed with enzyme marker. Then, a washing process is carried out to effect the B-F separation between the substance 2 and labeled reagent 3 bound with the carrier 1 due to the antigen-antibody reaction and free substances 2 and reagent 3 which are not bound with the carrier 1. Next, a color reagent which selectively reacts with the labeling enzyme is added and a reaction liquid is colorimetered to detect the enzyme activity of the labeling enzyme.
FIG. 2 shows successive steps of the sandwich method in which use is made of an insoluble carrier 5 having fixed thereto antibody or antigen which is reactive with antigen or antibody substances in a sample to be tested. At first, the carrier 5 and the sample 6 are mixed to effect the antigen-antibody reaction between the substances 6 in the sample and the antibody or antigen fixed to the carrier 5. Then, the B-F separation is carried out by means of the washing step. Next, a labeled reagent 7 is added to effect the antigen-antibody reaction. The labeled reagent is prepared by marking it with an enzyme substance selectively reactive with the substance 6 to be analyzed. Then, after the B-F separation is effected again, a color reagent reacting with the labeling enzyme in the labeled reagent 7 is added and a test liquid thus obtained is colorimetered to detect the activity of the labeling enzyme.
Usually, these competitive method and sandwich method have been performed by a manual operation. In this case, many carriers contained in a carrier container are supplied into the reaction vessel one by one by the manual operation and also the carrier supplied in the reaction vessel is manually discharged from the reaction vessel after the end of the analysis for the sample. However, in the automatic analyzer which performs automatically the immunological analysis, it is necessary to supply and/or discharge the carriers automatically into and/or from successive reaction vessels one by one in a precise manner.